1. Technical Field
The present invention relates to an optical module that includes a tunable interference filter extracting light of a predetermined wavelength from incident light and an optical measurement device including the optical module.
2. Related Art
Generally, an interference filter is known in which one pair of reflective films face each other, and light of a predetermined wavelength out of incident light that is strengthened through multiple interferences of the one pair of reflective films is transmitted or reflected (for example, see JP-A-2009-251105).
In the optical filter device (interference filter) disclosed in JP-A-2009-251105, one pair of substrates face each other, and, in one substrate of the substrates, a movable portion (first portion) and a diaphragm (second portion) that holds the movable portion so as to advance toward or retreat from the other substrate are disposed. In addition, one reflective film out of one pair of reflective films (mirrors) is formed in the movable portion, and, in the other substrate, the other reflective film facing the reflective film formed in the movable portion is formed. In this optical filter device, by controlling a voltage applied to an electrostatic actuator disposed between one pair of substrates, the movable portion is displaced by an electrostatic attractive force, and thereby the gap between the one pair of reflective films can be changed.
However, in the above-described interference filter, there is a case where the diaphragm bends due to a change in the ambient temperature. In contrast to this, a system is known that controls the driving of an MEMS device in accordance with a change in the temperature (for example, JP-T-2007-518138).
In the system disclosed in JP-T-2007-518138, a temperature sensor is disposed in the MEMS device, a driving voltage is selected from a lookup table based on a signal transmitted from the temperature sensor, and the selected driving voltage is input to a voltage adding circuit.
However, in JP-T-2007-518138 described above, since the temperature sensor is disposed in the MEMS device, in a case where the temperature sensor is disposed in the interference filter, the wiring of the temperature sensor becomes complicated, whereby the number of wirings is increased. Particularly, in a case where the temperature sensor is disposed in a small-size interference filter, there are problems in that it is difficult to acquire a position at which a connection terminal of the wiring of the temperature sensor is disposed or the layout of the wirings, and the wiring configuration becomes complicated. In addition, in a case where the interference filter is mounted in the optical module, in addition to a filter driving circuit such as the electrostatic actuator, a driving circuit of the temperature sensor needs to be arranged, whereby the wiring configuration of the optical module becomes complicated.